1. Field of the Invention
This invention pertains generally to the field of display systems such as, but not limited to, aircraft display systems.
2. Description of the Related Art
Two vision systems employed commonly in the aviation industry are the synthetic vision system (“SVS”) and the enhanced vision system (“EVS”). The SVS typically employs a terrain database to create a three-dimensional perspective of the scene in front of the aircraft on a two-dimensional display unit, whereas the EVS typically employs image sensor(s) to acquire real-world image data representative of an image that may be presented on the screen of one or more display units. Each vision system has its advantages and its disadvantages. One of the advantages of the SVS is that the image is not affected by meteorological conditions; however, one of its disadvantages is its inability to display actual objects location in the scene in front of the aircraft.
There are systems which simultaneously combine SVS image data with EVS image data. One such system has been disclosed by Wenger et al in U.S. Pat. No. 7,605,719 entitled “System and Methods for Displaying a Partial Images and Non-Overlapping, Shared-Screen Partial Images Acquired from Vision Systems,” wherein a visual spectrum camera system may be used to determine where the EVS image data will be employed and the SVS image data will be employed in a combined image data.
When an SVS generates synthetic image data, it may generate two arrays: a synthetic pixel image array and a depth array populated with multiple values, where each value may be a measurement of depth (i.e., slant range) between the aircraft and each point on the surface represented by a corresponding pixel within the synthetic pixel image array. Because there may be times at which an image generated by the EVS may be disadvantageous (e.g., poor meteorological conditions), a pixel cutoff distance could be defined and used in conjunction with the depth array to determine whether a pixel should be defined with SVS image data or EVS image data.